The present disclosure relates generally to the assignment of Internet Protocol (IP) addresses in wireless networks. More particularly, the present disclosure relates to increasing the speed of the assignment of IP addresses in wireless networks such as wireless local-area networks (WLANs).
Networking technologies such as WLAN require that a unique network address be assigned to each communicating device. IPv4 and IPv6 are the standard protocols used for these network communications, and have several ways in which the unique IPv4 or IPv6 device addresses can be assigned. The types of address assignment include static addressing, where the addresses are manually assigned by an administrator; dynamic addressing, where addresses are automatically assigned by a server, for example according to Dynamic Host Configuration Protocol (DHCP); and link-local addressing, where addresses are automatically assigned without a server.
Link-local addressing is useful in networks that are formed in an ad-hoc manner. These networks can include Wi-Fi Infrastructure, Wi-Fi IBSS, or Wi-Fi peer-to-peer networks. Such networks do not have centrally-coordinated address assignment or DHCP servers. According to applicable standards, a device having a link-local addressing mechanism first checks whether a DHCP server is available by sending DHCP requests. The device must retransmit the DHCP request multiple times before determining, after a significant delay, that no DHCP server is available. Only then does the device use link-local addressing to obtain a local address.
This delay presents a significant usability problem. Establishing a network connection between two devices can take 30 to 60 seconds just to determine whether DHCP is available. These long delays severely impact the user experience of mobile device connectivity.